studio: Depend on lib cssnano, gone missing during a merge. #344

Author: epost

studio/package.json

@@ -25,6 +25,7 @@
   "license": "Commercial",
   "devDependencies": {
     "concurrently": "^5.0.2",
+    "cssnano": "^4.1.10",
     "parcel-bundler": "^1.12.4",
     "purescript": "^0.13.5",
     "purescript-psa": "^0.7.3",